Tree nut allergy: current overview and recommendations

Abstract

In recent years, tree nut allergies have significantly increased globally, particularly in advanced countries, including Japan. The 2020 nationwide survey on immediate-type food allergies in Japan revealed that tree nuts ranked third among causative foods, showing a sixfold increase compared to 2011. Tree nut allergies manifest severe symptoms, and walnuts and cashew nuts in particular cause frequent reactions. Clinical features include early childhood onset, a high frequency of allergic reactions, including anaphylaxis at the first intake of tree nuts, and frequent complications of atopic dermatitis and other food allergies. Raising awareness to prevent unforeseen tree nut anaphylaxis is crucial. For very high-risk children, evaluating specific IgE antibody titers before the first intake, and based on the results, conducting oral food challenge tests or carefully introducing the allergen at home are considered beneficial. This approach contributes to overall patient well-being by reducing unnecessary food avoidance. Based on the latest literature, this article provides a comprehensive overview of tree nut allergies and offers recommendations for preventing tree nut-induced anaphylaxis.